/**
 * Created by semdy on 2016/9/6.
 */
(function(EC){
    "use strict";

    /**
     * Easing
     * **/
    var Easing = {

      Linear: {

        None: function (k) {

          return k;

        }

      },

      Quadratic: {

        In: function (k) {

          return k * k;

        },

        Out: function (k) {

          return k * (2 - k);

        },

        InOut: function (k) {

          if ((k *= 2) < 1) {
            return 0.5 * k * k;
          }

          return - 0.5 * (--k * (k - 2) - 1);

        }

      },

      Cubic: {

        In: function (k) {

          return k * k * k;

        },

        Out: function (k) {

          return --k * k * k + 1;

        },

        InOut: function (k) {

          if ((k *= 2) < 1) {
            return 0.5 * k * k * k;
          }

          return 0.5 * ((k -= 2) * k * k + 2);

        }

      },

      Quartic: {

        In: function (k) {

          return k * k * k * k;

        },

        Out: function (k) {

          return 1 - (--k * k * k * k);

        },

        InOut: function (k) {

          if ((k *= 2) < 1) {
            return 0.5 * k * k * k * k;
          }

          return - 0.5 * ((k -= 2) * k * k * k - 2);

        }

      },

      Quintic: {

        In: function (k) {

          return k * k * k * k * k;

        },

        Out: function (k) {

          return --k * k * k * k * k + 1;

        },

        InOut: function (k) {

          if ((k *= 2) < 1) {
            return 0.5 * k * k * k * k * k;
          }

          return 0.5 * ((k -= 2) * k * k * k * k + 2);

        }

      },

      Sinusoidal: {

        In: function (k) {

          return 1 - Math.cos(k * Math.PI / 2);

        },

        Out: function (k) {

          return Math.sin(k * Math.PI / 2);

        },

        InOut: function (k) {

          return 0.5 * (1 - Math.cos(Math.PI * k));

        }

      },

      Exponential: {

        In: function (k) {

          return k === 0 ? 0 : Math.pow(1024, k - 1);

        },

        Out: function (k) {

          return k === 1 ? 1 : 1 - Math.pow(2, - 10 * k);

        },

        InOut: function (k) {

          if (k === 0) {
            return 0;
          }

          if (k === 1) {
            return 1;
          }

          if ((k *= 2) < 1) {
            return 0.5 * Math.pow(1024, k - 1);
          }

          return 0.5 * (- Math.pow(2, - 10 * (k - 1)) + 2);

        }

      },

      Circular: {

        In: function (k) {

          return 1 - Math.sqrt(1 - k * k);

        },

        Out: function (k) {

          return Math.sqrt(1 - (--k * k));

        },

        InOut: function (k) {

          if ((k *= 2) < 1) {
            return - 0.5 * (Math.sqrt(1 - k * k) - 1);
          }

          return 0.5 * (Math.sqrt(1 - (k -= 2) * k) + 1);

        }

      },

      Elastic: {

        In: function (k) {

          if (k === 0) {
            return 0;
          }

          if (k === 1) {
            return 1;
          }

          return -Math.pow(2, 10 * (k - 1)) * Math.sin((k - 1.1) * 5 * Math.PI);

        },

        Out: function (k) {

          if (k === 0) {
            return 0;
          }

          if (k === 1) {
            return 1;
          }

          return Math.pow(2, -10 * k) * Math.sin((k - 0.1) * 5 * Math.PI) + 1;

        },

        InOut: function (k) {

          if (k === 0) {
            return 0;
          }

          if (k === 1) {
            return 1;
          }

          k *= 2;

          if (k < 1) {
            return -0.5 * Math.pow(2, 10 * (k - 1)) * Math.sin((k - 1.1) * 5 * Math.PI);
          }

          return 0.5 * Math.pow(2, -10 * (k - 1)) * Math.sin((k - 1.1) * 5 * Math.PI) + 1;

        }

      },

      Back: {

        In: function (k) {

          var s = 1.70158;

          return k * k * ((s + 1) * k - s);

        },

        Out: function (k) {

          var s = 1.70158;

          return --k * k * ((s + 1) * k + s) + 1;

        },

        InOut: function (k) {

          var s = 1.70158 * 1.525;

          if ((k *= 2) < 1) {
            return 0.5 * (k * k * ((s + 1) * k - s));
          }

          return 0.5 * ((k -= 2) * k * ((s + 1) * k + s) + 2);

        }

      },

      Bounce: {

        In: function (k) {

          return 1 - Easing.Bounce.Out(1 - k);

        },

        Out: function (k) {

          if (k < (1 / 2.75)) {
            return 7.5625 * k * k;
          } else if (k < (2 / 2.75)) {
            return 7.5625 * (k -= (1.5 / 2.75)) * k + 0.75;
          } else if (k < (2.5 / 2.75)) {
            return 7.5625 * (k -= (2.25 / 2.75)) * k + 0.9375;
          } else {
            return 7.5625 * (k -= (2.625 / 2.75)) * k + 0.984375;
          }

        },

        InOut: function (k) {

          if (k < 0.5) {
            return Easing.Bounce.In(k * 2) * 0.5;
          }

          return Easing.Bounce.Out(k * 2 - 1) * 0.5 + 0.5;

        }

      }

    };

    EC.provide({
        Easing: Easing
    });

})(window.EC);